The answer is Yes, according to two fascinating new studies presented this summer at the Associated Professional Sleep Societies, held in Boston. Studies repeatedly show that white people get more and better-quality sleep than people of other races, while black people are more likely to get shorter, more restless sleep.
In one of the studies presented at the Boston conference, white participants from the Chicago area were found to get an average of 7.4 hours of sleep per night, while Hispanics and Asians averaged 6.9 hours and blacks 6.8 hours. In addition, sleep quality—which the study defined as ease in falling asleep and length of uninterrupted sleep—was also higher for whites than for blacks.
While socioeconomics play a role in the quality of sleep people get, researchers have found that even when they control for socioeconomic factors the differences remain. For example, a 2005 study adjusted for education, income and employment status and found that black men still slept 82 minutes less per night than white women, who slept better than anybody in the study.
The implications of such findings are profound, with possible connections to more health problems in the African American community—obesity, diabetes, heart problems—and even less productivity and poorer school performance.
“When people aren’t sleeping as well during the night, they aren’t as productive during the day, and they’re not as healthy,” Dr. Mercedes R. Carnethon, associate professor of preventive medicine at Northwestern University Feinberg School of Medicine, told the New York Times. “It’s a self-perpetuating cycle.”
But are we talking biological differences or just people living in different circumstances?
“We’re not at a point where we can say for certain is it nature versus nurture, is it race or is it socioeconomics,” said Dr. Michael A. Grandner, a research associate with the Center for Sleep and Neurobiology at the University of Pennsylvania. But when it comes to sleep, “there is a unique factor of race we’re still trying to understand.”
Researchers believe the magic bullet might be stress, which is one thing they can’t really tease out in a lab or on a questionnaire.
“We had no way to control for stress, and there are social stresses an African-American man might feel that a white man with the same income and education level wouldn’t,” said Dr. Kristen Knutson, assistant professor of medicine at the University of Chicago and an author of the study.
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“People who feel they have control over their lives were able to feel secure at night, go to sleep, sleep well, and wake up well in the morning and do it all over again,” said Dr. Lauren Hale, associate professor of preventive medicine at Stony Brook University on Long Island, referring to a study she conducted in 2009. “That’s part of the cycle not just for blacks and minorities, but other disadvantaged populations.”
There are other fascinating connections that researchers have found that are specific to race and gender. For Hispanic men, being divorced or widowed was particularly detrimental to their sleep, while never being married was more likely to take a toll on the sleep of Asian men. For Asian women, a lack of education was more likely to lead to sleep problems than similarly educated white women. And men of all races who were in relationships slept better than single men, regardless of relationship quality; for women, the quality of the relationship was more likely to affect sleep.
“There’s an effect of socioeconomics,” said Dr. Grandner, a lead author of the study, “but it’s not really the economic. It’s more about the socio.”
And then there are the kids. According to a 2010 study conducted by Dr. Hale for the National Institutes of Health, black and Hispanic children in America are far less likely to have regularly enforced bedtimes than white children. White children were also more likely to have “language-based” bedtime routines — those that involve reading or storytelling — both of which are associated with a wide range of cognitive and behavioral advantages.
These are routines that the body becomes accustomed to, that continue later in life.
“If routines are absent, especially these language-based routines, then children may be missing out on opportunities to develop and sleep optimally,” Hale said.